JPH074906B2 - Electromagnetic shield laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electromagnetic shield material, and more particularly to an electromagnetic shield material using a conductive polymer.

Conventional technology ICs, LSIs are used for various electronic devices such as computers.
The electromagnetic waves of high frequency pulses generated there are leaked to the outside and have a great impact on peripheral devices.

Conventionally, two methods have been mainly considered as a so-called EMI countermeasure in a device housing for preventing leakage of electromagnetic waves from such electronic devices to the outside.

One is a surface treatment method that forms a conductive film on the surface of a plastic molded product, and the other is a molding method of a composite plastic conductive agent in which a conductive filler is mixed into plastic.

However, in the former surface treatment method, for example, when a metal plating method is used, the types of resin that can be plated are limited, and when a metal foil tape is used, it is not sufficient in terms of weight reduction, and the conductivity is further reduced. It is possible to use a paint, but if it is not applied to a thickness of 50 μm or more, a uniform coating film cannot be obtained and a sufficient shielding effect cannot be obtained. Further, in the latter molding method, it is necessary to mix 30 to 40% of filler, so that there is a problem that a material having high mechanical strength cannot be obtained.

On the other hand, polymers such as polyacetylene, polythiophene, and polypyrrole that have conjugated double bonds in the main chain are known to have electric conductivity comparable to that of metals when doped with a small amount of impurities, but most of them are ,
It has not been put to practical use because it has poor stability in air, cannot maintain a metallic state for a long time, and has insufficient mechanical strength.

SUMMARY OF THE INVENTION The present invention has been made to solve the above drawbacks, and an object of the present invention is to provide a lightweight and tough electromagnetic shield material that does not have such drawbacks.

As a result of various studies conducted by the present inventors, it was noted that the electrochemically polymerized pyrrole-based polymer complex in the presence of an aromatic anion has excellent performance such as mechanical strength. The present invention has been completed.

That is, the present invention relates to an electromagnetic shield material having as a constituent requirement a layer containing a polymer complex of an aromatic anion and a pyrrole-based monomer as a main component.

More specifically, the structure of the electromagnetic shield laminate of the present invention comprises the electrolytically polymerized pyrrole or its derivative and the unsubstituted or substituted aromatic in the presence of a salt of pyrrole or its derivative and the unsubstituted or substituted aromatic anion. It usually has a layer of a polymer complex containing an anion as a main component in the form of a film.

The layered product of the present invention can be obtained by disposing such a layer of the pyrrole-based polymer complex on the support selected according to the purpose.

The pyrrole-based polymer complex used in the present invention is produced by placing a solution of a pyrrole-based monomer and an anion salt in a solvent in a predetermined electrolytic cell, and then performing an electrolytic polymerization reaction by anodic oxidation.

The pyrrole-based monomer used in the present invention is not particularly limited. For example, in addition to pyrrole, 3,4-alkyl (carbon number: 1 to 4) pyrrole, 3,4-arylpyrrole, 3
(Or 4) alkyl-4 (or 3) -arylpyrrole (carbon number; 1-4) can be mentioned.

The content of pyrrole or its derivative in the electrolytic solution can be appropriately selected, but is usually preferably 0.02 to 1.00 mol, and particularly preferably 0.10 to 0.30 mol. If it is less than 0.02 mol, the film forming efficiency is low, while if it is 1.00 mol or more,
It tends to be difficult to obtain a uniform film.

As the unsubstituted or substituted aromatic anion which is a constituent of the present invention, various kinds can be used, but the same or different substituents selected from hydrogen or lower alkyl (C number; 1 to 3), nitro or cyan can be used. Preference is given to using at least one anion of aromatic sulphonic acid or likewise substituted aromatic carboxylic acid, with anions of parasulphonic acid giving particularly good results.

Incidentally, this anion is not only one kind in the polymer complex,
You may make it contain 2 or more types as needed. Further, this anion is usually used as a metal salt in addition to at least one kind of reaction solution, and as the cation in this case, for example, alkali metals such as Li, Na and K, ammonium such as (Et) N and (Bu) N, H, etc. can be mentioned.

The content of the aromatic anion metal salt in the electrolytic solution can be appropriately selected, but is usually preferably 0.01 to 1.2 mol. If it is less than 0.01 mol, the polymerization efficiency is poor, and
When it is 2 mol or more, the undissolved electrolyte is dispersed in the membrane,
Mechanical strength decreases.

Solvents used for producing the pyrrole-based polymer complex layer of the electromagnetic shield laminate of the present invention include water, methanol, acetonitrile, benzonitrile, propylene carbonate, γ-butyltacron, nitrobenzene, dioxane, dimethylformamide, and acetone. A solvent can be mentioned. From the viewpoint of reactivity, acetonitrile, benzonitrile, and propylene carbonate are preferable, and when water is not used or the solvent does not contain water, a more homogeneous polymer complex is formed, and a film having high tensile strength tends to be obtained. is there.

The pyrrole-based polymer complex used in the present invention is produced by subjecting a solution of the above-mentioned pyrrole-based monomer and an aromatic anion salt to a solvent, to a predetermined electrolytic cell, and then performing an electrolytic polymerization reaction by anodic oxidation. It If you need more,
You may add additives, such as a catalyst.

The structure or shape of the electrolytic cell and the electrodes arranged therein are not particularly limited, and those commonly used in the field of electrolysis can be applied, for example, a rotating disk electrode or a multilayer structure electrode can be used, and an anode and a cathode. It is possible to use those separated by a porous film made of glass or polymer.

Examples of the material forming the electrodes include metals such as Au, Pt and Ni, oxides thereof, SnO ₂ , In ₂ O ₃ and composite electrodes or coating electrodes thereof. It is preferable to use it because a film having a strong polymer complex can be obtained.

The electric current supplied during the electrolysis reaction affects the reactivity, the homogeneity of the polymer complex, the strength of the film, the film thickness, etc., so it is necessary to appropriately adjust it according to the required product quality.
It is preferable to set the current density so that it is usually in the range of at least 0.1 to 1.5 mA. It seems that when the content is set within this range, polymerization is easy and the strength becomes strong.

The bonding state of the pyrrole-based monomer and the anion constituting the pyrrole-based polymer complex thus obtained is not exactly clear, but as far as the present inventors have analyzed, the pyrrole-based polymer is the main component. It is considered that a pyrrole-based monomer / anion is formed as a complex at a molecular ratio of about 3/1 on the polymer chain.

The structure of the electromagnetic shield laminate of the present invention has various modes depending on the purpose, and a typical structure example will be described below with reference to the drawings.

1 to 4 are examples used as an adhesive tape or an adhesive film, and FIG. 5 is an example used as a box-shaped structure.

The laminates shown in FIGS. 1 and 2 are obtained by forming the pyrrole polymer complex layer 3 on the pressure-sensitive adhesive layer 2. For example, it is manufactured by coating an acrylic emulsion or the like as a pressure-sensitive adhesive on the film of the above layer and laminating it with release paper.

The laminated body of FIGS. 3 and 4 has the adhesive layer 2 in FIG.
It is produced in the same manner except that a conductive filler 4 such as carbon or fine metal powder is dispersed therein, and has not only an electromagnetic shield but also an electrostatic shield effect.

FIG. 4 shows that the protective layer 5 is further formed on the pyrrole polymer complex layer of FIG. By providing such a protective layer 5, storage stability, flame resistance, and folding resistance can be improved, so the material thereof is appropriately selected according to the purpose.

In FIG. 5, a molded product 6 made of plastic in a predetermined box shape is used as a reinforcing agent, and a pyrrole polymer complex layer 7 is arranged on the reinforcing material 6, which can be applied as a shield box. The shape of such a box shape can be appropriately selected according to the application.

Effect The electromagnetic shield film laminate of the present invention using the pyrrole-based polymer complex is not only tough, but also lightweight and thin, and provides a high-performance shielding effect.

Hereinafter, the present invention will be described in more detail with reference to production examples of a pyrrole-based polymer complex and examples in which the shield effect was confirmed using the same.

Production Example 1 Nesa glass plate (ITO, SnO and InO vapor-deposited conductive glass film) as an anode, and Ni plates as a cathode are placed in an electrolytic cell with one sheet facing each other, and then the electrolytic solution having the composition is put in the electrolytic cell. It was

Pyrrole (0.1 mol) p-toluenesulfonic acid (0.05 mol) acetonitrile This solution was subjected to an anodic oxidation reaction under the following conditions to form a film of a polymer complex on a Nesa glass plate.

Current density 1.0mA / cm ² ; Applied voltage 4.0V The properties of the generated polymer complex film are shown below.

Film thickness 50 μm (20 C / cm ² ); Dope amount 35% Tensile strength 10,500 psi; Electric conductivity 90 S / cm Measuring method (same for the following manufacturing examples) Film thickness: By stylus film thickness meter. Dope amount: The amount of aromatic anion with respect to the pyrrole ring 1, which is measured by elemental analysis.

Electrical conductivity: By four-terminal method. Tensile strength: Tensilon UTM-III (manufactured by Toyo Baldwin) is chucked at a width of 1 cm and a length of 3 cm.

Production Example 2 An electrolytic solution having the following composition was placed in the same electrolytic bath as that used in Production Example 1.

Pyrrole (0.2 mol) Na paratoluenesulfonate (0.05 mol) Propylene carbonate This solution was subjected to a low current electric field anodic oxidation reaction at a current density of 0.8 mA / cm ² to form a film of the polymer complex on a Nesa glass plate.

The properties of the generated polymerized complex film are shown below.

Film thickness 23 μm (6 C / cm ² ); Dope amount 38% Tensile strength 11,000 psi; Electric conductivity 37 S / cm Production Example 3 An electrolytic solution having the following composition was added to the same electrolytic cell as in Production Example 1. I put it in.

Pyrrole (0.2 mol) Orthotoluenesulfonic acid Na (0.01 mol) Acetonitrile This solution was subjected to anodic oxidation reaction under the following conditions to form a film of a polymer complex on a Nesa glass plate.

Current density 1.1mA / cm ² ; Applied voltage 3.5V The properties of the generated polymer complex film are shown below.

Film thickness 45 μm (14 C / cm ² ); Dope amount 34% Tensile strength 10,000 psi; Electric conductivity 40 S / cm Comparative Production Example An electrolytic solution consisting of the following composition was added to the same electrolytic cell used in Production Example 1. I put it in.

Pyrrole (0.2 mol) Lithium perchlorate (0.1 mol) Acetonitrile This solution was anodized by constant current electrolysis at a current density of ² mA / cm ² to form a polymerized complex film on a Nesa glass plate.

The properties of the generated polymerized complex film are shown below.

Thickness 48 μm; Dope amount 33% Tensile strength 3300 psi; Electrolytic conductivity 28 S / cm Example 1 Pyrrole polymer complex film (0.34 g / cm 3) obtained in Production Example 1
Acrylic resin adhesive Arontac [S-121 manufactured by Toagosei Co., Ltd.] is applied to ² ) to a thickness of about 4 μ, and 150 mm × 150 mm,
After fixing to an acrylic plate with a thickness of 2 mm, the attenuation factor (dB) was measured by the Takeda RIKEN method to confirm the electric field shielding effect. The results are shown in the table below.

The Takeda RIKEN method is a general method for confirming the electric field shield effect.The one fixed on the above acrylic plate is used with a Takeda Riken spectrum analyzer TR4172, and the electric field rod antenna spacing is set to 10 mm and the attenuation factor is set. Is measured.

Example 2 Pyrrole-polymerized complex film (0.16 g / c) obtained in Production Example 2
m ² ), the attenuation rate (d
B) was measured. The results are shown in the table below.

Example 3 Pyrrole polymer complex film (0.31 g / c) obtained in Production Example 3
m ² ) and carbon powder (average particle size of approx.
The attenuation rate (dB) was measured in the same manner as in Example 1 except that 2.5 μ) was dispersed by about 30%. The results are shown in the table below.

Example 4 A pyrrole polymer complex film having a shape as shown in FIG. 2 was obtained in the same manner as in Production Example 3 except that a Neza glass plate having “knurled” was used as the anode. Other than using this pyrrole polymer complex film (0.30 g / cm ² ),
The attenuation rate (dB) was measured in the same manner as in Example 1. The results are shown in the table below.

Example 5 In Example 2, a pyrrole polymer complex film (0.33 g / cm
² ) The attenuation factor (dB) was measured in the same manner as in Example 1 except that a protective layer was formed by blending urethane [Hitaroid 3008] and a curing agent [Desmodur N75] and then curing the mixture. did. The results are shown in the table below.

Comparative Example 1 The acrylic plate used in Example 1 was prepared by applying a copper acrylic conductive paint to a thickness of about 35 μ (0.31 g / cm ² ) and the attenuation rate (dB) was measured in the same manner. . The results are shown in the table below.

Comparative Example 2 In Comparative Example 1, about 16 parts of nickel acrylic conductive paint was used.
The attenuation rate (dB) was measured in the same manner except that the one coated to a thickness of μ (0.52 g / cm ² ) was used. The results are shown in the table below.

Comparative Example 3 A Scotch conductive tape [1267] (3M, 1267) (1.02 g / cm ² ) in which an adhesive was applied to an A1 foil (thickness: about 90 μ) was attached to the acrylic plate used in Example 1, The attenuation rate (dB) was measured in the same manner as in Example 1. The results are shown in the table below.

As is clear from this table, it can be understood that the pyrrole polymer complex film has an excellent shielding effect, and that the laminate of the present invention formed using this is useful as an electromagnetic shield material.

[Brief description of drawings]

1 to 4 are structural examples of a laminated body of the present invention in the form of a tape or a film, and FIG. 5 is a sectional view of an example in the form of a box. 1 …… Release paper; 2 …… Adhesive layer 3,7 …… Pyrrole polymer complex layer 4 …… Conductive filler; 5 …… Protective layer 6 …… Plastic molding reinforcement layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiichi Kanto 2-1-501 Takeyacho, Suita City, Osaka Prefecture (56) References JP-A-59-166529 (JP, A) SAIKAI 59-109193 (JP, U)

Claims (1)

[Claims] 1. An electromagnetic shield laminate having a layer of a pyrrole-based polymer complex containing an aromatic anion and a pyrrole-based monomer as main components.